1. Field of the Invention
The present invention relates to a dust separating apparatus for use in a vacuum cleaner, which draws in air and dust from a surface being cleaned, separates dust from the air and discharges clean air. More particularly, the present invention relates to a multi-cyclone dust separating apparatus, which centrifuges dust from air by plurality of stages.
2. Description of the Related Art
Various types of dust separating apparatuses have been employed in vacuum cleaners. Among these, a cyclone type dust separating apparatus, which is easy to use and almost permanently usable, is rapidly replacing disposable dust bag or dust filter dust separating apparatuses. FIG. 1 is a perspective view of a canister type vacuum cleaner, which employs a cyclone type dust separating apparatus.
Referring to FIG. 1, a vacuum cleaner 10 generally includes a cleaner body 11 which is divided into a motor driving chamber 12 where a motor (not shown) is installed, and a cyclone mount chamber 13 where a cyclone dust separating apparatus 30 is installed, a suction nozzle 21, an extension hose 22, and a flexible hose 23. The vacuum cleaner 10 generates suction force by driving the motor (not shown), and draws in dust and air into the cleaner body 11 through the suction nozzle 21, extension hose 22, and flexible hose 23. The vacuum cleaner 10 then separates dust from the drawn-in air using the cyclone dust separating apparatus 30, and collects the separated dust. The clean air is discharged out via the motor driving chamber 12.
The cyclone dust separating apparatus 30 induces a whirling air current in the drawn-in air, and thus the dust is separated from the air by the centrifugal force of the whirling air. Meanwhile, the general practice is that a cyclone body 31 of the cyclone dust separating apparatus 30 is formed in cylindrical shape, and air inlet 33 and outlet (not shown) are provided near the upper end of the cyclone body 31. The air inlet 33 is in fluid communication with the flexible hose 23 via the inlet port 14, and the air outlet (not shown) is in fluid communication with the motor driving chamber 12 via an outlet port 15. A dustbin 32 is provided to the lower part of the cyclone body 31 to hold dust separated from the air, and is generally formed in a cylindrical shape to correspond to the shape of the cyclone body 31. In other words, a conventional cyclone dust separating apparatus 30 overall has a cylindrical configuration.
Accordingly, as shown in FIG. 2, a dead space S is generated between the cyclone dust separating apparatus 30 and the cyclone mount chamber 13 housing the cyclone dust separating apparatus 30. In order to corresponding to the shape of the motor, the motor driving chamber 12 is usually square in section, while the adjoined cyclone mount chamber 13 is approximately half circle in section. Because the cyclone dust separating apparatus 30 has cylindrical shape, such different shape of the cyclone mount chamber 13 and the cyclone dust separating apparatus 30 inherently causes one or more dead spaces S therebetween. Meanwhile, the cyclone dust separating apparatus 30 has a limited height to be employed in the cyclone mount chamber 13, and thus, the dustbin 32 has a limited height too. As a result, dust capacity is limited.
A multi-cyclone dust separating apparatus has recently been introduced, which filters dust by more than two stages and, thus, improves dust collecting efficiency. One example of such multi-cyclone dust separating apparatus is disclosed in WO02/067755 and WO02/067756 to Dyson Ltd. According to the above patents, upstream cyclone as the first cyclone and downstream cyclone as the second cyclone are arranged in vertical arrangement, which requires height of the cyclone dust separating apparatus to extend. This limits the application of the multi-cyclone dust collecting apparatus to upright type vacuum cleaners. In other words, the multi-cyclone dust separating apparatus cannot be efficiently applied to canister type vacuum cleaners for home use. Additionally, as the entire path for air of the cyclone dust collecting apparatus is long, loss of suction force increases.
In order to overcome such shortcomings of the conventional arts, the same Applicant as the present application has developed a multi-cyclone dust separating apparatus as disclosed in Korean Patent No. 0554237. In the above patent, the multi-cyclone dust separating apparatus is provided with a plurality of second cyclones, which are arranged around the first cyclone. Therefore, the overall height of the multi-cyclone dust separating apparatus decreases, and dust collecting efficiency increases. However, compacter vacuum cleaners are still required.